This invention relates to a method for writing and viewing magnetic, human readable characters and a viewing means therefore which can be used, for example, in a security system like a credit card system employing "debit" balances.
Statistics indicate that only about one third of the adult population in the United States has accepted the concept of a "credit card" or credit purchases. Another one third of the adult population has not established a satisfactory credit base and is consequently refused the use of credit cards by financial institutions. The final one third of the adult population does not believe in credit and prefers the "pay as you go" concept.
To avoid collection difficulties associated with the second one third of the adult population mentioned, and to appeal to the credit avoidance tendencies of the final one third, the concept of a "debit" card has been introduced. Private banking institutions, as well as national credit card companies, are establishing "debit card systems", which in effect, represent pre-deposited funds. Because the account balances associated with the debit cards represent the pre-deposited funds, they can be used by the credit-risky, one third of the adult population, and should be acceptable to the final one third of the adult population which prefers the "pay as you go" concept.
A debit card user deposits cash into his account, and his account is maintained by electronic terminals which deduct from his account the amounts of purchases as they are made by him. His debit card is continually updated by the terminals so that his card always has a balance thereon which reflects the amount which he has available for purchases. In order to keep track of the balance on his debit card, the user of the card must keep a record of his own balance between monthly or quarterly statements while making purchases. Unless the user of a debit card keeps a record of his account, as for example, in a record book which he carries with him, the user has no ready reference as to the amount of purchases left on the debit card, as the balance on his debit card is not in human readable form. Under these conditions, it is possible that he may unintentionally attempt to make purchases for which he has no funds.
Many people do not like to keep records of the type mentioned above, and consequently, the use of a "debit card" system may not be too attractive to them.
If the electronic terminal used with the debit card could write the updated balance and other pertinent date on the card in human readable form, the need for manually maintaining a balance could be avoided. However, for practical reasons, there are certain criteria which must be met in any system employing such a debit card. For example, while the updated balance on the card should be written in human readable form, it should normally be invisible so that it can not be read by a casual handler of the card, like a retail sales or bank clerk. Some viewing means is necessary to enable the user or owner of the card to read the normally invisible balance thereon when desired, and the cost of the system employing such a debit card should be low. The present invention meets the above criteria.
Some prior art disclosures which generally relate to prepayment systems, magnetic recording on record mediums, and means for viewing magnetically recorded data are shown in the following U.S. patents:
2,971,916, 3,013,206, 3,221,315, 3,683,382, 3,845,499, 3,846,830, 3,852,571, 3,873,975, 3,878,367, and 3,929,278.